Sports direct founder Mike Ashley
Business Insider / Thomas Colson
LONDON — Billionaire Sports Direct owner Mike Ashley allegedly held drinking contests during management meetings, once vomited in a fireplace, and took naps in meetings when bored, according to a Bloomberg report of a court hearing on Monday.

Ashley is being sued by Jeffrey Blue, a former banker who advised Sports Direct, over an alleged £15 million ($19.5 million) bonus he was promised.

Blue, a former Merrill Lynch banker, was hired in 2013 to spearhead Sports Direct's takeover bids. He alleges that Ashley promised him the bonus payment at a London bar in 2013 if he doubled the retailer's share price from £4 to £8.

Ashley disputes the claim and says the promise was part of the regular banter at alcohol-fuelled business meetings, and was not supposed to be taken seriously, Bloomberg says.

A witness statement from Blue said Sports Direct management meetings he attended "were like no other senior management meeting I had ever attended in all my years of investment banking experience."

He said: "It was effectively a "pub lock-in" with alcohol continuing to be served well beyond closing hours and fish and chips or kebabs being provided."

Blue said that on one occasion, Ashley challenged a young analyst to a drinking competition during a management meeting which saw the pair downing pints of lager between vodka shots, and ended with Ashley vomiting into the pub's fireplace to "huge applause" from his senior management team.

Blue also alleged that Ashley would "take a nap" underneath tables in meetings he found boring.

Ashley will give evidence on Wednesday and will say the conversations were never intended to be taken seriously, Bloomberg said. The case is expected to last for longer than a week.